why or how did my battery on my galaxy S6 blow up?

[AC Question]

So I jumped into a pool with my galaxy S6. I realised immediately and swam out. I let it sit in rice for a couple days and tried to turn it on. Nothing so now it's been several days and just for hope I tried to charge it overnight and when I woke up the battery was exploded and the phone was incredibly hot, why or how did this happen?

 

[belodion]

The water may be the cause.